Question

The percentage purity of copper sulphate is:
A. $80\%$
B. $98\%$
C. $92\%$
D. $88\%$

Answer 1

In chemistry, the percentage purity of a substance ca be understood as the ratio of the mass of the pure chemical (also known as molar mass) to the total mass of the sample that has been collected of the substance, and then we need to multiply this value by 100.

Complete Step-by-Step Answer:
Before we move forward with the solution of the given question, let us first understand some important basic concepts.
To represent percentage purity in a mathematical form, we can say:
Percentage purity of substance
Water of crystallization can be understood as the water that is present in the crystal structures of salts and metal complexes. These water molecules are not directly bonded to the metal cation, but instead are present as interstitial defects. When crystallization of salts or metal complexes takes place from water or moist solvent, many compounds incorporate water molecules in their crystalline framework.
Copper sulphate is the salt formed by the negative sulphate ion which has an oxidation state of (-2) and the positive copper ion. Copper has the capability of exhibiting two oxidation states, (+1) and (+2). In this particular case, the dipositive ion of copper (copper ion with oxidation state +2) is used. The chemical formula of copper sulphate is $CuS{O_4}$ . Copper sulphate is usually found in the form of blue coloured crystals. This colour is obtained by the water molecules present due to the water of crystallization. Most of the pure copper sulphate that is commercially available has only water as the impurity in its structure and the purity percentage is about $98\%$ .

Hence, Option B is the correct option

Note: Copper sulphate is a fungicide used to control bacterial and fungal diseases of fruit, vegetable, nuts, and field crops. Some of the diseases that are controlled by this fungicide include mildew, leaf spots and apple scab.